This investigation analyses the social dumping discourse in the international trading system. It studies the cross-cutting occurrence of a simplistic, Manichean and essentially polarizing rhetoric within the international trading system, specifically son two highly polarizing occurrences: the controversy over social clause within the "multilateral subsystem" and the posted workers controversy in the "regional subsystem", specifically in the context of the European Union expansion.Therefore, the subject of this text is not the social dumping itself, no as an autonomous phenomenon neither as a derivation of the dumping (commercial). So, the study starts from a fast review of the basic's theories about international trade and the history of multilateralism and multilateral trade organizations. It goes on to present the evolution of the idea of dumping from the earliest ideas with Jacob Viner until it reaches the status of a well-defined legal-economic phenomenon, but which, when integrated with the GATT, as instrumental in the commercial defense as the anti-dumping duties, was eventually used as trade protectionism tools or development policy instruments that put the free trade interests of the developed country against to the developing in the WTO.Next, this work try to understand the discourse, the rhetoric, or the accusation, of social dumping as a narrative subterfuge commonly employed by populists to antagonize the interests of developed countries with those of developing countries in both multilateral trade and promotion of the opposition North of the South and East of the West in the European Union. Next, the idea of marketization is offered as an example of a more lucid approach that can help to clarify the processes grossly addressed by the rhetoric of social dumping.The ending is about the endorsement of the importance of the social dumping as a discourse, once that the demarcation attempts or conceptualization of social dumping as derived from dumping has been failed.